


A Morning of Fun

by NihilismPastry



Category: Undertale (Video Game)
Genre: Dirty Talk, Dom!Sans, F/M, Fingering, Handsy Sans, Master/Pet, Multi, Protective Papyrus, Sensitive bones, Underswap AU
Language: English
Status: Completed
Published: 2016-09-16
Updated: 2016-09-16
Packaged: 2018-08-14 19:17:36
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,983
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8025817
Author URL: https://archiveofourown.org/users/NihilismPastry/pseuds/NihilismPastry
Summary: You go over to your boyfriends' house to see a surprise, a little fun becomes something more.





	A Morning of Fun

**Author's Note:**

> I wanted to try my hand at Underswap. That's really the only reason this story even exists.

You'd gotten the call at seven on a Sunday morning. The bubbly skeleton on the other side of the line shrieking something almost unintelligible,  while you held your phone a good three inches from your ear. Once you could no longer hear screaming you hesitantly brought the contraption back, your arm tense and fingers twitching. "Just let me wiggle on some pants, Sans. I'll be over in a few."

You hung up and fell back into your blankets, eyes shut and a groan escaping your lips. Sans had been expecting a package in the mail for weeks now. He never actually _told_ you what it was, but he often ranted about how magnificent it was, and how even the greatest of puzzle crafters would be jealous. You had been amused by that excitement over the past three weeks, but hearing it so early on your only day off of work was...Well, Sans was just lucky you loved him. 

You pulled you body out of bed and kept your pajama top on, a bright green tank top, and shrugged on a pair of denim shorts. After having your morning coffee, you headed out the door and to your boyfriends' house. They only lived a brisk walk away in the apartment complex across the street. You hurried up the metal steps, hoping you woke every neighbor along the way, and got to the third floor. You wondered down the doors until you found one with a very neat eight painted against the brown wood. You downed the rest of your coffee, you didn't need Sans sneaking into it, and knocked on the door. 

Your fist hadn't even left the wood before the door swung open, an excited Sans bouncing in place, his pupils morphed into glittering stars. "You actually made it!"

"Of course I did," you bent down and gave him a peck on the forehead. "you asked me to come over, didn't you?"

He grinned and took your hand as you straightened back up. The apartment wasn't all that big, just a two bedroom one bath place that always smelled damp and musty. You took off your shoes at the door, and allowed Sans to lead you to the living room. Sitting on the small coffee table was a...chess set. "Tada!" Sans was bouncing on the balls of his feet now, his smile wider than the Grand Canyon. "Isn't it cool?"

The board was made of clear and frosted glass, with the pieces having a similar set up. Next to the board was a wooden case with a pale blue rage on top. You knelt down on the cold linoleum and carefully picked up the frosted king piece with you thumb and middle finger. It felt much heavier than it looked, but still had delicate dips and grooves in the glass. It must have been way more expensive than the ones you usually saw at the store. "It's a beautiful set, Sans. I didn't know you were into chess."

Sans knelt on the other side of the table. "I didn't know about it until I saw a book at the library. It had a lot of cool games that makes you smarter, and chess was one of them! I got Papy to get me a chess set of my own so I could become the greatest puzzle master ever!" 

You smiled slightly, his enthusiasm beginning to rub off on you. That enthusiasm was probably why you dated Sans in the first place.

"So did you ask her yet?" A scratchy and very tired voice asked. You glanced behind you to see Papyrus leaning against the doorway to his bedroom. His clothes were a bit more rumpled than usual, and there was an unlit cigarette in his mouth. He must have just woken up. 

"Morning, Papyrus." He just gave you a nod as his fingers slipped into his hoody pocket in search of something. You turned back to Sans who had a dusting of baby blue along his cheek bones. "What do you need to ask, Sans?"

"Um...Do you want to teach me to play?" He had begun to twiddle with his gloved hands. "I remember you said your grandmother taught you to play, so I thought you could teach me." 

You set the king piece back on the board, and carefully swiveled it around so the frosted side was facing Sans, and the clear side was facing you. "As long as I can be the clear pieces." 

That seemed to evaporate all of the small skeleton's worries as he dropped his hands down into his lap, and payed close attention as you explained how the pieces moved. There was a flick and the faint smell of ash over powered the mold smell in the living room. You knew Papyrus was watching you, watching how you treated his brother. You knew the taller skeleton was protective of his brother, and that even if you were dating both of them, he would end you if he thought you were cheating. 

Once the explanation was completed you let Sans go first. He gave the pieces a hard stare for a few moments before he opened with his knight. His eyes flicked up to you and he gave a mischievous smile. You smiled back and went forward one space with your pawn. For the next twenty minutes the two of you moved pieces, capturing them, and all round playing a decent game. Even Papyrus moved from his place in the doorway, to come sit next to you. Sans was surprisingly good at the game and managed to block a few of your moves, and more than once you asked if he played before. 

"Nope, I wanted my first game to be with you." 

However, all good things eventually must come to an end. You slid your rook forward and grinned. "Check mate."

"Huh, already?!" 

You just shrugged and leaned back on your palms. Your butt was starting to get numb, and the coffee was only just starting to take effect. "Yeah, but you did a really good job Sans. If I didn't know any better, I'd say you played this before. Chess takes a ton of practice, I've been playing since I was six, you just started today." You gave him a smile. "I'm sure you'll beat me before too long."

Sans stared at the game board for a moment before he nodded slowly. "So it takes hard work and dedication. I think I like this game even more now, it wouldn't be fun if it was so easy." He jabbed a finger in your direction. "The Magnificent Sans shall beat you next time!"

"I'm sure you will Sans. Just keep practicing and you'll get better in no time." You glanced over to Papyrus, who looked half asleep leaning against you. "You wanna take a go at it, Papyrus?"

The skeleton opened one socket to look at you and shrugged, causing his bones to dig into your own shoulder. "I dunno, it looks like a pretty _dice-_ y game. You'll probably manage to kick my ass all the way _home_ and back _."_

You rolled your eyes while Sans scrambled up to his feet with an indignant huff. "Those puns were terrible, they didn't even have anything to do with chess!" 

"You're right, guess I gotta up my _game_." Sans's sockets narrowed while you tried to make your snort sound like a cough. Papyrus seemed to notice it, however, and a lazy smirk curled over his mouth. "At least I have _Uno_ person who likes my jokes."

Sans opened his mouth, but nothing managed to come out. After a moment he glared, shut his mouth properly, and left the room. The sound of pots and pans slamming together soon followed. Huh, looks like you were gonna have to choke down some of Sans's cooking. 

"Oh god," You shook your head. "that one was really bad, man. Now he's gonna go on a food frenzy."

Papyrus shrugged and closed his eye sockets again, all of the amusement slipping off his face. "Worth it."

You shook your head again and began to set the pieces back into their respective places. Every so often you brought one close to your face, examining the details that were blown into the glass. It really was a nice set, much nicer than you could get in a store around this part of town. And having ordered it online, it probably cost Papyrus a fortune...Or this month's rent. However you didn't bother to bring it up, you learned a long time ago to let Papyrus do what he wanted when it came to spoiling you and Sans. He always managed to make ends meet anyway, so you guess it didn't matter in the end.

You gently bumped the skeleton's shoulder. "Hey, do you wanna go a round?"

He stared at the neatly set up board for a moment before shrugging. "Fine, but you get the other side of the table."

"Seriously?"

"I'm comfortable."

You made a show of rolling your eyes and sighing, before getting to your feet and going to the other side of the the table. You sat crossed legged on the floor and crossed your arms over your chest. "Happy?"

"It makes my _chess_ -t pulse with joy." He moved a pawn forward one space. "Your go."

The two of you went at it for much longer than you and Sans. In fact the smaller skeleton had finished cooking his tacos and had brought them out before you managed to land Papyrus in check. If Sans was a talented beginner, then Papyrus was already on your level. For every move you made, he had one to counter. It was one of the rare moments that Papyrus proved he wasn't a lazy idiot capable of only terrible puns and sleeping. This was one of those times that he showed his actual cunning and thinking abilities, and then exploited the living hell out of them.

"Check mate."

You blinked and looked up at the smirking skeleton. You were most certainly in check mate, his knight had successfully cornered you. There were no more moves to make on or off the board. Swallowing your pride you smiled slightly and held out your hand for him to shake. "That was a pretty good game, Papy. Been awhile since someone did me in that good." 

"Yeah, that was a very close victory, Papy!"

A faint tinge of orange spread over his cheek bones. You weren't sure if it was the accidental innuendo, or the use of his nickname that you rarely used. He flicked his finger and warm magic tingled across your palm like hundreds of little ants. Unbidden, your hand moved up and down as if someone was shaking it. "Guess I learned from the master."

"Who, Garry Kasparov?"

"No," He flicked his finger upward, and you smacked your hand to your forehead. You keened out an insulted whine that Papyrus ignored. "you."

Your face warmed from the rare compliment. But it barely had time to sink in before Sans enveloped you in a hug, his arms wrapped as far around your waist as they could, and his face buried in your boobs. "You're super smart and cool! You teach us how to play chess, and about the seasons, and all those humans holidays!" He nuzzled further into your chest, and you have to actively remind yourself that he can't suffocate. "You're the best girlfriend ever, Sweetheart!"

You pressed the nails of your free to the smaller skeleton's skull and scratched it lightly. A contended moan rumbled from the skeleton and he straddled your hips. "It's really nothing special, babe. I only know all this stuff because I'm human, you could have learned the same thing from anyone else on the surface."

You glanced up when your hand fell off your face. Papyrus had stood up and was leaving the room, his hands entrenched in his hoody pockets. You opened your mouth to protest, but he disappeared in a crackle of magic. You gasped and your back went stiff when Sans bit your chest. It wasn't exceptionally hard, just a gentle nip that was meant to catch your attention. "I don't like it when my pet acts so cruel. You never want to accept our compliments, that's really mean, don't you think?"

Gloved fingers trailed down your hips and gripped your ass, pressing you closer to the small body on top of you. Magic sparked and curled around the both of you, the calming smell of hot tea became strong. Your body trembled and you hunched over, head buried in Sans's shoulder. "Sans-"

The skeleton pushed himself out of your chest and grabbed your face in his hands. "No, you're going to get your punishment, Sweetheart. You should never doubt my words, I love you so much, but you pretend that I don't."

You bit your lip and glanced around the room. Papyrus was still gone, no doubt at Muffet's and downing another bottle of honey. You encircle your arms around Sans's shoulders and lean down, pressing your lips to his teeth. Without any hesitation on his part, he opened his mouth and let his tongue snake into yours mouth. He tasted like lime and cilantro with a hint of garlic, it wasn't all together unpleasant. When your lungs began to ache you pulled away, spit connected the two of you, a strange kink that Sans had. 

Suddenly he rocked his weight forward, and you hit the ground with a thud. The salvia connecting you broke, but Sans didn't seem to notice as he leared down at you. His glassy pupils were narrowed, and his eternal smile was wider than it should have been. Slowly he raised one hand to his mouth and bit the index finger to his glove and pulled it off. Smooth pale bones were revealed, there were cuts and nicks here and there, but nothing too out of the ordinary. He set the glove on the table behind him and took off the other. This one was worse for wear with a giant crack down the side of his entire hand. There was a rough bone like scab over it, but the crack was still evident through the thin healing trick. 

He pulled your tank top up, revealing the smooth skin of your stomach. He pressed two fingers to your skin and a short burst of magic swirled in your insides. It felt like small tendrils pressing down inside of you and massaging your poor organs. You sucked in a breath when his fingers trailed upwards, a pale blue path of magic following in their wake. "I'm going to fuck you," He said, voice low in a rumbling purr. "And I'm going to keep fucking you until you realize that I love you more than anything in the world. Understand?" You nodded, not sure if you trusted your voice. This didn't seem to matter to Sans as he kissed you again, a hand sliding up and squeezing your breast through your bra.

"Good, pet."

He squeezed your breast a bit harder and began to grind his pelvis into yours. The thick denim of your shorts muted most of the feeling, and made you more irritated than anything. You brought your hands up and gently looped your hands through the belt loops. "Master, my pants. I can't feel you with them on."

He paused in his movements for a moment before nodding. He slid off of you and stripped off your pants. A smirk twisted his smile as he looked down at your exposed core. "No underwear today, Pet?"

You moaned when he slid two fingers into your moist heat. He flexed his fingers a few times before shoving them in as deep as they would go. You yelped and arched your back, and Sans laughed at you. "Master~." He grunted and began to shove his fingers back and forth into your tight pussy. His bones had a wonderful texture that slid and ground perfectly into your muscles. It didn't take long for your juices to slip down his hand and into the linoleum. 

You stared at the skeleton above you. His free hand caressed his ribs under his shirt, and blue dusted his cheeks. Yet there was a hard look still in his eyes, one that made your heart pound against your ribs. You reached up and kissed him again, your arms wrapped around his neck to bring him close. He didn't tell you to do it, but you also weren't wearing your collar. Technically you were allowed this. 

Sans fingers curled and reached deep inside you. Gasps and half curses welled to your lips, but we're drowned out by kisses. When you finally reached that peek with your eyes shut and a scream on your lips, Sans grabbed the back of your head and yanked on your hair. Your eyes fluttered open and you stared at him, thighs trembling and a blush on your face. "I want to see you cum, Pet. Doing this to you, seeing you like this, it's the greatest act of love I can give." He pressed his forehead to yours. " _ **Now** **cum**_." 

Your months of training paid off as your insides clamped down on his fingers. A wave of hot pleasure courses through your veins, and it took everything you had not to shut your eyes and just bask in it. Sans's fingers began to slow down, the smirk on his face easing away to his usual happy smile. Sometimes his blatant flips in mood disturbed you, but as you laid on his living room floor with your heart beating fast and his fingers knuckle deep in your cunt, you couldn't help but smile. "I love you, Sans."

The monster leaned forward and kissed you again. "You know that's just round one, _**right**_?" 

**Author's Note:**

> I love the idea of Dom! Blueberry, it's cute. Also, Garry Kasparov is the best chess player in recorded history. 
> 
> If you wanna see more cool content like this you should check out my tumblr. I take requests, review AUs, and review fan fiction. http://nihilismpastry.tumblr.com


End file.
